Horn having a diaphragm vibrated by an electromagnetic motor



June 5, 1956 WHITE Er 27493542 HORN HAVING A DIAPHRAGM VIBRATED BY AN ELECTROMAGNETIC MOTOR Filed June 29, 1955 53 HO 2| 390 1 26 25 I52 w L L *6 INVENTORS Joe White 22 By William I? Brundage Fig 2 7' /'r Attorney United States Patent HORN HAVING A DIAPHRAGM VIBRATED BY AN ELECTROMAGNETIC MOTOR Joe White and William F. Brundage, Anderson, Ind., as-

signors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Original application March 11, 1949, Serial No. 80,854,

now Patent No. 2,677,875, dated May 11, 1954. Digidledlgnd this application June 29, 1955, Serial No.

2 Claims. (Cl. 340-403) This invention relates to a sound signal or horn having a diaphragm vibrated by an electromagnetic motor and cooperating with a projector. In this type of born, the production of a proper tone is dependent upon vibration of the diaphragm at a frequency in resonance with the natural frequency of the air in the projector. The frequency of diaphragms made according to the same specification will vary due to variations in the diaphragm material. Since the projector frequency is non-adjustable, it is necessary to make an adjustment of the diapragm frequency so that a resonant condition will exist. Furthermore, it is necessary to prevent the occurrence of conditions which would cause the diaphragm frequency to change during the use of the horn. This is a division of S. N. 80,854, filed March 11, 1949, now Patent 2,677,875.

It is an object of the present invention to simplify the manner of supporting the horn terminal member and of connecting it with the horn magnet coil and to extend a portion of the circuit breaker assembly through an opening in the horn cover.

A further object of the present invention is to provide for attachment of magnet coil leads to terminals in such a manner that the leads do not break when the horn is subjected to vibration.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein preferred embodiments of the present invention are clearly shown.

In the drawings:

Figure l is a top plan view of the horn according to the present invention with the cover removed.

Figure 2 is a sectional view along line 2--2 in Figure 1 showing the cover in position.

In the drawings, the numeral 20 designates a horn according to the present invention. This horn is provided with a projector 22 and a frame or base 25 which has a flange 26 having holes 27 which has upright lugs 29 to which the horn magnet assembly is secured. The base 25 has a resistor assembly attached thereto. This assembly comprises a resistor disc 35, a terminal clip 36, an insulating washer 37, a metal washer 38, a rivet 39 (received by a hole 39a in base 25), and a non-conducting sleeve 40 surrounding the rivet. After these parts are assembled to the base as shown in Figure 2, the upper end of rivet 39 is upset. The underside of the resistor 35 is grounded on frame 25. The upper side of resistor 35 is electrically connected with the terminal clip 36 which has prongs 41 which are formed around the insulation 42 and wire 43 and whose end is engaged by prongs 44 also integral with clip 36. The wire end is united with the prongs 44 and the clip 36 by welding.

As set forth in the parent application, the central opening in base 25 receives an electromagnetic assembly 50 which is carried by lugs 29 on the frame. This assembly comprises a plurality of E-shaped laminations of magnetic iron and steel plates and which assembly also has a coil ice which is preferably wound in rectangular form and which has lead wires which are enclosed in sleeves of insulating material and which are connected with the circuit breaker assembly which will be hereinafter described.

The armature assembly for the horn 20 comprises a rod 70 which has threaded ends 71 and 72 and a threaded cylindrical portion 73 which receives an armature 74, a plate 75 having a flange 76, a leaf spring '77 and a nut '78. when these parts are assembled, the flange 76 of the plate 75 fits around the squared end of the spring 77 and the flat side of the nut 78 which threadedly engages the portion 73. Spring 77 is provided with three holes which register with three holes 30a in a shelf 30. These holes receive rivets 80 by which the leaf spring 77 and the other part shown in Figure 1 are attached to the shelf 30. The threaded end portions 71 of the armature assembly is secured with the diaphragm 21 as shown in Figure 2. After the electromagnetic assembly 50 is secured upon the frame 25, and the armature assembly is assembled therewith by passing the rod 70 through a suitable hole in the magnet core assembly and the spring 77 is placed upon shelf 30 with the holes thereof in register with the holes in the shelf 30, then a loose assembly or stack of parts including a circuit breaker is assembled. This stack of parts includes, in addition to the spring 77, a metal spacer 81, an insulating plate 83, a connector plate 34, a terminal 82, an insulating plate 85, a connector plate 86, a leaf spring 87, an insulating plate 88, three rivets 30 and non-conducting tubes which surround the rivets 80. The bracket 89 supports a contact 91 normally engaged by a contact 92 attached to the leaf spring 87 and projecting through a hole provided in the plate 88. The lower end of the rivets 80 are swedged over at 93 in order to secure the stack of parts to the shelf 30. The heads of the rivets 80 contact the bracket 89 so that contact 91 is connected to ground through brackets 89, rivets 80, shelf 30 and frame 25 which is grounded by its mounting upon the frame of the vehicle which a ground strap connects with a terminal of the storage battery. A nut 94, which is engageable with the plate 88, and a lock nut 95 are screwed on the end 72 of the rod 70.

The terminal 82 which is in electrical engagement with the connector plate 84 has its free end bent downwardly; and said end is arranged to provide a cup-shaped member 110. The member receives a screw 111 for attaching thereto a clip 112 and a clamp 114 which has a tang 115 received by a hole in member 110 whereby rotation of the clamp 114 is prevented and is served to prevent accidental rotation of the screw 111 by frictional engagement with its head.

When all of the parts of the horn are assembled, as disclosed in the patent supra, of which this application is a division, the back shell of the horn is installed. This shell 150 has tangs 151 which are bent into suitable notches 152 in the projector 22. The shell is provided with an opening 153 which is lined with a rubber-like grommet 154 through which the cup part 110 of the terminal 82 extends. This rubber-like grommet will provide a seal between the cup-shaped part 110 and the cover 150 and will insulate the cup part 110 from the cover 150.

While the embodiments of the present invention as herein disclosed, constitute preferred forms, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. In an electromagnetic horn, a circuit breaker and terminal assembly comprising a metal frame and a stack of parts mounted thereon, rivets securing the parts to the frame said parts including horn magnet coil terminal plates, circuit breaker members insulated from each other and carrying engageable contacts, one of said members contacting one of the coil terminal plates and the other member contacting the rivets, and including a horn terminal plate engaging the other of the coil terminal plates and insulated from the support and from the first mentioned coil terminal plate, a cover attached to the frame and having an opening adjacent the stack, a nonconducting grommet lining the opening, said horn terminal plate having an extension which projects through said opening and provides for the attachment of a conductor thereto.

2. In an electromagnetic horn, a circuit breaker and terminal assembly comprising a metal frame and a stack of parts mounted thereon, rivets securing the parts to the frame, said parts including members insulated from each other and carrying contacts and magnet coil terminal members one of which is in contact with a contact carrying member thus placing a magnet coil connected with its terminal members in a series circuit with the contact carry- References Cited in the file of this patent UNITED STATES PATENTS Mendel et al Oct. 5, 1937 Stieglitz Sept. 19, 1944 

